CN113677989B

CN113677989B - Peak integral correction without parameter adjustment

Info

Publication number: CN113677989B
Application number: CN202080025379.5A
Authority: CN
Inventors: L·伯顿; S·A·塔特
Original assignee: DH Technologies Development Pte Ltd
Current assignee: DH Technologies Development Pte Ltd
Priority date: 2019-06-12
Filing date: 2020-06-10
Publication date: 2024-05-28
Anticipated expiration: 2040-06-10
Also published as: US12019057B2; US20220187259A1; EP3983793A1; EP3983793A4; WO2020250158A1; JP2022537622A; CN113677989A

Abstract

The separation device is instructed to separate the compound from the sample over a period of time. The mass spectrometer is instructed to measure a plurality of intensities of at least one ion of the separated compounds over a period of time, thereby producing a chromatogram. At least one peak of the at least one ion is identified from the chromatogram using a peak finding algorithm. Two or more different peak integration regions of the at least one peak are calculated by applying a peak finding algorithm with two or more different values of the at least one peak finding parameter. Two or more plots of at least one peak are simultaneously displayed on a display device, each plot graphically showing a different peak integration region. In response, data is received from the user selection device, the data indicating a user selection of one of the two or more drawings.

Description

Peak integral correction without parameter adjustment

Related applications

The present application claims the benefit of U.S. provisional patent application Ser. No.62/860,310, filed on 6/12 of 2019, the contents of which are incorporated herein by reference in their entirety.

Background

The teachings herein relate to apparatus and methods for peak integration in chromatography systems, including but not limited to Liquid Chromatography (LC) and Gas Chromatography (GC). More specifically, two or more integration regions for the chromatographic peak are displayed to the user simultaneously, and the user is allowed to select a preferred integration region. This approach reduces the time it takes to view and select the appropriate integration region of the chromatographic peak. The method is independent of the detection system (mass spectrometry (MS), ultraviolet (UV), etc.) used.

The apparatus and methods disclosed herein may be implemented in conjunction with a processor, controller, microcontroller, or computer system (such as the computer system of fig. 1).

Mass spectrometry background

Mass Spectrometry (MS) is an analytical technique for detecting and quantifying compounds based on the analysis of the m/z values of ions formed from the compounds. MS involves ionizing one or more compounds of interest from a sample, generating parent (pre) ions, and mass analyzing the parent ions.

Tandem mass spectrometry or mass spectrometry/mass spectrometry (MS/MS) involves ionizing one or more compounds of interest from a sample, selecting one or more parent ions of the one or more compounds, cleaving the one or more parent ions into child (product) ions, and mass analyzing the child ions.

Mass spectrometers are typically coupled to a chromatographic or other separation system in order to identify and characterize eluted compounds of interest from a sample. In such a coupled system, compounds in the eluting solvent are ionized and a series of mass spectra are obtained at specified time intervals. These times range from, for example, 1 second to 100 minutes or more. Intensity values derived from the series of mass spectra form a chromatogram. For example, the sum of all intensities generates a Total Ion Chromatogram (TIC), and the intensity of one mass value generates an extracted ion chromatogram (XIC).

Peaks found in the chromatogram are used to identify or characterize known peptides or compounds in the sample because they elute at a known time called the retention time. More particularly, the retention time of the peak and/or the area of the peak is used to identify or characterize (quantify) the known peptide or compound in the sample.

In conventional separation coupled mass spectrometry systems, parent ions of known compounds are selected for analysis. MS/MS scanning is then performed for a mass range including parent ions at each separation interval. The intensities of the sub-ions found in each MS/MS scan are collected over time and analyzed as, for example, an XIC or collection of spectra.

Both MS and MS/MS can provide qualitative and quantitative information. The measured parent or child ion spectrum may be used to identify molecules of interest. The intensities of parent and daughter ions can also be used to quantify the amount of compound present in the sample.

Separation device background

As described above, mass spectrometers are typically coupled to separation systems or devices to identify and characterize compounds of interest that elute from a sample. Such separation devices may include, but are not limited to, liquid Chromatography (LC) devices, gas chromatography devices, capillary electrophoresis devices, or ion mobility devices. LC devices are typically used in conjunction with mass spectrometers to quantify the amount of a compound of interest in a sample.

Fig. 2 is an exemplary diagram of an LC device 200 for a mass spectrometer. LC device 200 includes two separate devices. It includes a High Performance Liquid Chromatography (HPLC) device 210 and a direct infusion or injection device 220.

In HPLC apparatus 210, valve 215 is used to select one of two solvents 211 or 212. Solvent 211 or 212 is moved to valve 215 using pumps 213 and 214, respectively. The sample 216 is mixed with the selected solvent using mixer 217 and the resulting mixture is sent through a Liquid Chromatography (LC) column 218. For example, the sample 216 is selected using an autosampler 219.

In the direct infusion or injection device 220, the sample has been mixed with a solvent in the fluid pump 221. Fluid pump 221 is shown as a syringe pump, but may be any type of pump.

The valve 230 is used to select the use of the HPLC device 210 or the direct infusion or injection device 220. The selected mixture or mobile phase components are sent over time from valve 230 to an ion source (not shown) of a mass spectrometer (not shown).

Problem of chromatographic peak integration

As described above, the result of the split coupled mass spectrometry experiments is typically TIC or XIC. These chromatograms are essentially a collection of intensity changes over time. Chromatograms are typically used to determine the amount of a particular compound present in a sample. To quantify or quantify a compound, the parent or daughter ion peaks in the chromatogram are integrated. Integration of a peak generally refers to finding the region under the peak in the chromatogram.

For all quantitative works involving chromatographic peak integration, the accuracy of peak-finding (peak-finding) within the chromatogram is important. This is especially true for many fields of application (pharmaceutical, clinical, etc.), where users routinely manually review all chromatograms to correct any chromatograms that are not sufficiently well integrated. The peaks are re-integrated as usual even in cases where the total peak area difference may not appear to be particularly large to a person skilled in the art.

In all existing separation coupled mass spectrometry software, the screening process involves visual inspection of a set of chromatograms and corresponding default peak scores (and default peak finding parameters). When the default score is not satisfied, the user adjusts the peak finding parameter, applies a new value, and visually observes the result. This process is repeated until the user is satisfied. In some cases, the user essentially gives up-either at the beginning or after several failed attempts to change the parameters-and manually draws the peak baseline. Some laboratories do not allow such a fully manual integration (which is considered too subjective) and the user must continue to adjust the parameters. The peak baseline is essentially the boundary of the region at the base of the peak.

FIG. 3 is an exemplary interaction table 300 displayed to a user by a peak finding algorithm and shows peak finding parameters used by the peak finding algorithm to integrate peaks. For example, table 300 is generated by one of the SCIEX peak-finding algorithms. Note that table 300 allows the user to alter parameters to re-integrate a particular peak.

Fig. 4 is an exemplary plot 400 of chromatographic peaks displayed to a user by a peak finding algorithm and showing the correct integration of chromatographic peaks according to the parameters of fig. 3. Using the parameters of fig. 3, the peak finding algorithm applies the peak baseline 411 to integrate, or find, the area under the peak 410. Note that peak baseline 411 has vertical and horizontal components. The vertical component of peak baseline 411 separates the region of peak 410 from interfering peak 420. Note also that peak baseline 411 is shown as a vertical line and a horizontal line. In some embodiments and for some algorithms, the baseline may be a curve. For example, the baseline may be a curve that follows peak 420 to more accurately subtract its contribution.

Fig. 5 is an exemplary plot 500 of chromatographic peaks displayed to a user by a peak finding algorithm and shows incorrect integration of chromatographic peaks according to the parameters of fig. 3. Using the parameters of FIG. 3, the peak finding algorithm applies the peak baseline 511 to integrate, or find, the area under the peak 510. In fig. 5, the integration of the peak 510 is incorrect, as the integration includes contributions from interfering peaks 520. In other words, the peak baseline 511 applied does not exclude contributions from the interfering peak 520. To correct this integration, the skilled reviewer may modify one or more parameters of fig. 3 to re-integrate peak 520 of fig. 5. Unfortunately, this is an iterative and manual process, depending on the procedure used by the current peaking algorithm.

Thus, the fundamental problem with the process used by current peak finding algorithms is that it takes too much time to re-integrate the incorrect peak. More specifically, iterative adjustment of the peak finding parameters of incorrectly integrated peaks takes too much time. This is especially true because it is often not immediately clear which of the peak seeking parameters to adjust and how much.

Furthermore, well-trained, experienced analysts are typically able to make corrections with reasonable efficiency, but far from being the case for novice. In fact, perhaps a greater problem is the frustration of the user, except for the time actually required, because it is difficult for them to find a set of parameters that will integrate in the desired way.

Thus, additional systems and methods are needed to reduce the time it takes to review and select the appropriate integration of chromatographic peaks and to select the appropriate integration without expert knowledge of the peak-finding parameters of one or more peak-finding algorithms.

Disclosure of Invention

A system, method and computer program product for selecting an integration region of a chromatographic peak are disclosed. The apparatus includes a separation device, a mass spectrometer, a display device, a user selection device, and a processor.

The processor instructs the separation device to separate the compound from the sample over a period of time. The processor instructs the mass spectrometer to measure a plurality of intensities of at least one ion of the separated compounds over a period of time, thereby producing a chromatogram. The processor identifies at least one peak of the at least one ion from the chromatogram using a peak finding algorithm. The processor also calculates two or more different peak integration regions for the at least one peak using a peak finding algorithm by applying the peak finding algorithm with two or more different values of the at least one peak finding parameter. The processor simultaneously displays two or more plots of at least one peak on the display device, each plot graphically showing a different peak integration region of the two or more different peak integration regions. In response, the processor receives data from the user selection device, the data indicating a user selection of one of the two or more drawings.

These and other features of applicants' teachings are set forth herein.

Drawings

Those skilled in the art will appreciate that the figures described below are for illustrative purposes only. The drawings are not intended to limit the scope of the present teachings in any way.

FIG. 1 is a block diagram illustrating a computer system upon which embodiments of the present teachings may be implemented.

Fig. 2 is an example diagram of an LC device of a mass spectrometer.

FIG. 3 is an exemplary interactive table displayed to a user by a peak finding algorithm and showing peak finding parameters used by the peak finding algorithm to integrate peaks.

FIG. 4 is an exemplary plot of chromatographic peaks displayed to a user by a peak finding algorithm and shows the correct integration of chromatographic peaks according to the parameters of FIG. 3.

FIG. 5 is an exemplary plot of chromatographic peaks displayed to a user by a peak finding algorithm and shows incorrect integration of chromatographic peaks according to the parameters of FIG. 3.

FIG. 6 is an exemplary display of three different possible credits for the same peak shown in FIG. 5, allowing a user to review multiple credits simultaneously and select a particular credit without requiring expert knowledge of the peak-finding parameters of a particular peak-finding algorithm, in accordance with various embodiments.

Fig. 7 is a plot of percent change in peak area according to a peak split factor parameter, according to various embodiments.

FIG. 8 is a schematic diagram of a system for selecting an integration region of a chromatographic peak, according to various embodiments.

Fig. 9 is a flow chart illustrating a method for selecting an integration region of a chromatographic peak, in accordance with various embodiments.

FIG. 10 is a schematic diagram of a system including one or more different software modules that perform a method for selecting integration regions of chromatographic peaks, according to various embodiments.

Before one or more embodiments of the present teachings are described in detail, those skilled in the art will recognize that the present teachings are not limited in their application to the details of construction, the arrangement of components and the arrangement of steps set forth in the following detailed description or illustrated in the drawings. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

Detailed Description

Computer-implemented system

FIG. 1 is a block diagram illustrating a computer system 100 upon which embodiments of the present teachings may be implemented. Computer system 100 includes a bus 102 or other communication mechanism for communicating information, and a processor 104 coupled with bus 102 for processing information. Computer system 100 also includes a memory 106, which may be a Random Access Memory (RAM) or other dynamic storage device, coupled to bus 102 for storing instructions to be executed by processor 104. Memory 106 may also be used for storing temporary variables or other intermediate information during execution of instructions to be executed by processor 104. Computer system 100 also includes a Read Only Memory (ROM) 108 or other static storage device coupled to bus 102 for storing static information and instructions for processor 104. A storage device 110, such as a magnetic disk or optical disk, is provided and coupled to bus 102 for storing information and instructions.

Computer system 100 may be coupled via bus 102 to a display 112, such as a Cathode Ray Tube (CRT) or Liquid Crystal Display (LCD), to display information to a computer user. An input device 114, including alphanumeric and other keys, is coupled to bus 102 for communicating information and command selections to processor 104. Another type of user input device is cursor control 116, such as a mouse, a trackball, or cursor direction keys for communicating direction information and command selections to processor 104 and for controlling cursor movement on display 112. Such input devices typically have two degrees of freedom in two axes, a first axis (i.e., x) and a second axis (i.e., y), which allows the device to specify positions in a plane.

Computer system 100 may perform the present teachings. Consistent with certain embodiments of the present teachings, results are provided by computer system 100 in response to processor 104 executing one or more sequences of one or more instructions contained in memory 106. Such instructions may be read into memory 106 from another computer-readable medium, such as storage device 110. Execution of the sequences of instructions contained in memory 106 causes processor 104 to perform the processes described herein. Alternatively, hardwired circuitry may be used in place of or in combination with software instructions to implement the present teachings. Thus, embodiments of the present teachings are not limited to any specific combination of hardware circuitry and software.

In various embodiments, computer system 100 may be connected across a network to one or more other computer systems (e.g., computer system 100) to form a networked system. The network may comprise a private network or a public network such as the internet. In a networked system, one or more computer systems may store and provide data to other computer systems. In a cloud computing scenario, one or more computers storing and providing data may be referred to collectively as a server or cloud. For example, one or more computer systems may include one or more web servers. For example, other computer systems that send data to and receive data from a server or cloud may be referred to as client or cloud devices.

The term "computer-readable medium" as used herein refers to any medium that participates in providing instructions to processor 104 for execution. Such a medium may take many forms, including but not limited to, non-volatile media, and transmission media. Non-volatile media includes, for example, optical or magnetic disks, such as storage device 110. Volatile media includes dynamic memory, such as memory 106. Transmission media includes coaxial cables, copper wire and fiber optics, including the wires that comprise bus 102.

Common forms of computer-readable media or computer program product include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, or any other magnetic medium, a CD-ROM, digital Video Disk (DVD), blu-ray disk, any other optical medium, thumb drive, memory card, RAM, PROM, and EPROM, a FLASH-EPROM, any other memory chip or cartridge, or any other tangible medium from which a computer can read.

Various forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to processor 104 for execution. For example, the instructions may initially be carried on a magnetic disk of a remote computer. The remote computer can load the instructions into its dynamic memory and send the instructions over a telephone line using a modem. A modem local to computer system 100 can receive the data on the telephone line and use an infrared transmitter to convert the data to an infrared signal. An infrared detector coupled to bus 102 can receive the data carried in the infrared signal and place the data on bus 102. Bus 102 carries the data to memory 106, and processor 104 retrieves and executes the instructions from memory 106. The instructions received by memory 106 may optionally be stored on storage device 110 either before or after execution by processor 104.

According to various embodiments, instructions configured to be executed by a processor to perform a method are stored on a computer-readable medium. The computer readable medium can be a device that stores digital information. For example, computer readable media includes compact disk read only memory (CD-ROM) for storing software as known in the art. The computer readable medium is accessed by a processor adapted to execute instructions configured to be executed.

The following description of various embodiments of the present teachings is presented for purposes of illustration and description. It is not intended to be exhaustive and does not limit the present teachings to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the present teachings. Furthermore, the described embodiments include software, but the present teachings can be implemented as a combination of hardware and software or separately in hardware. The present teachings can be implemented with both object-oriented and non-object-oriented programming systems.

Displaying multiple chromatographic peak integrals

As described above, the fundamental problem with the procedure used by current peak finding algorithms is that it takes too much time to re-integrate incorrectly integrated peaks. More specifically, manual and iterative adjustment of the peak finding parameters for incorrectly integrated peaks takes too much time. Furthermore, well-trained, experienced analysts are typically able to make corrections with reasonable efficiency, but far from being the case for novice.

In various embodiments, a plurality of different possible peak credits are displayed to the user simultaneously, and the user is allowed to select a preferred credit. This approach reduces the time it takes to review and select the appropriate integration of the chromatographic peaks by reducing the number of iterations. Essentially, many different integrals are generated in only one iteration.

The method also allows selection of an appropriate integral without requiring expert knowledge of the peak finding parameters of a particular peak finding algorithm. The peak finding parameter value will still be adjusted between a number of different possible peak integrals. But they are automatically adjusted. The user simply visually inspects the areas of the plurality of displayed peaks and selects the best drawn integral pattern to select the correct peak finding parameters for the peaks.

FIG. 6 is an exemplary display 600 of three different possible credits for the same peak shown in FIG. 5, allowing a user to review multiple credits simultaneously and select a particular credit without requiring expert knowledge of the peak-finding parameters of a particular peak-finding algorithm, in accordance with various embodiments. Plots 610, 620, and 630 graphically depict three different integrals of the same chromatographic peak. Each plot includes the shadows of the integrated regions and the peak baselines.

From plots 610, 620, and 630, the user can more quickly select the correct points. There is no iteration. The user need only visually inspect and compare the scores (areas) of plots 610, 620, and 630. Nor any peak finding parameter value. This is done automatically. To select the correct integration and peak finding parameter values, the user simply clicks on one of the plots 610, 620, and 630.

For example, a comparison of plots 610, 620, and 630 shows that in plot 620, peak baseline 621 excludes small interfering peak 520 at the beginning of peak 510, but does not exclude the shoulder at the end of peak 510. Accordingly, drawing 620 is likely to be selected by the user. As a control, in plot 610, peak baseline 611 excludes the shoulder at the end of peak 510 in addition to the small interfering peak 520 at the beginning of peak 510. As in fig. 5, in plot 630, peak baseline 631 does not exclude small interfering peak 520 at the beginning of peak 510.

Conventionally, for example, a table of peak finding parameter values (e.g., table 300 of fig. 3) and a single plot of integrated peaks (e.g., plot 500 of fig. 5) are displayed to a user. The user can then iteratively alter the peak-finding parameter values in the table and see a single updated plot of the re-integrated peaks.

In contrast, in various embodiments described herein, a single display of multiple plots of different points is presented to the user, such as the display shown in FIG. 6. The user may then click on a plot of the score to select the score and its peak finding parameter value.

In various embodiments, when the user enters "adjust integration mode," a plurality of different possible peak integrals are provided. Further, in various embodiments, a plurality of different possible peak integrals are determined in different ways.

In one embodiment, the administrator specifies initial different peak-finding parameter values. Thus, the administrator creates two or more sets of initially different peak-finding parameter values. This requires additional pre-administrator time, but is acceptable for trials that are expected to be used for a long time or by less trained operators.

In another embodiment, the values of one or more parameters vary within their useful ranges, and a representative value for each parameter is selected for each significantly different result. One exemplary peak finding parameter is a peak splitting factor.

Fig. 7 is a plot 700 of percent change in peak area according to a peak split factor parameter, in accordance with various embodiments. Plot 700 shows that only three different peak split factor values affect the percent change in peak area. Note that within the parameters studied, only three different peak splitting factor values affect the percent change in peak area. But this parameter varies within the range considered most useful.

All peak splitting factor values exceeding two provide the same percentage change in peak area as two. The different possible values of the parameters are not particularly numerous for most peak finding algorithms. At a minimum, the number of programmatically explored computers is not large. But for manual exploration this number may be "multiple".

Thus, it is possible to explore the parameter space almost completely. In various alternative embodiments, the "design of experiment" approach may be used to more efficiently explore space. Under the experimental design method, a subset of all possible parameter values is found and used. The subset may be selected randomly or may be based on some known information about the experiment.

In various embodiments, a combination of two or more peak finding algorithms is used to find a plurality of different integrals. For example, it is possible to combine radically different peak finding algorithms (such as MQ4 and AutoPeak of SCIEX) and vary the corresponding parameters for each algorithm.

In various embodiments, the number of different (but still reasonable) peak integrals is kept small. Furthermore, in various embodiments, even for laboratories that do not allow for full manual integration (i.e., baseline drawing), it is possible for the user to draw a manual baseline and then automatically select the parameter set that is closest to the integration (or allow the user to choose from a subset of the most similar integration). Or the selection may be iterative-the user selects a "tight" integral in a first step and then a fine-tuned integral in a second step.

In various embodiments, the value of the peak-finding parameter may still be displayed in a system that is at least partially directed to an experienced user. When the user selects one of the displayed possible credits, the parameter value changes to reflect the selection. The display of the parameter values may still be interactive to allow the user to further manually adjust the parameters.

In various alternative embodiments, the peak finding parameters and their values are not displayed, at least during routine peak screening. This is particularly desirable in cloud systems with data review in web browsers, because a simpler User Interface (UI) is often required compared to desktop systems.

In general, the calculation of many possible peak integrals does not require a significant amount of computer processing time. In various embodiments, however, if the calculation of possible peak integrals consumes a significant amount of computer processing time, the integrals may be pre-calculated and stored during the initial creation of the results or may be done immediately (on-the-fly) when the user selects to change a particular integral.

In various embodiments, a high quality integration algorithm is first used to minimize the number of peaks that need to be corrected. For example AutoPeak has a "more intelligent" shoulder detection than MQ4 and has a higher first pass accuracy and can therefore be used first.

Nevertheless, no peaking algorithm is-or may always be-perfect, so some manual correction is always required. Currently, once several peaks need to be corrected, the user must also understand the meaning of the different available parameters and how they might change the integral. As described above, the various embodiments described herein may eliminate the need to present parameters to the user, thus allowing inexperienced users to obtain good results.

In its simplest form, the embodiments described herein reduce the time required for peak integral correction. If the integral parameters can be largely removed from the peak screening user interface, this means that the user does not need to understand their meaning or use. This provides significant cost savings to the customer while also directly alleviating user frustration in parameter adjustment. Furthermore, as described above, the embodiments described herein reduce the time required for manual peak re-integration.

Chromatographic peak integration system

Fig. 8 is a schematic diagram 800 of a system for selecting integration regions for chromatographic peaks, in accordance with various embodiments. The system of fig. 8 includes separation device 810, mass spectrometer 820, display device 831, user selection device 832, and processor 830.

Processor 830 is used to control separation device 810 and mass spectrometer 820 or to provide instructions to separation device 810 and mass spectrometer 820 and to analyze data collected from mass spectrometer 820. Processor 830 controls or provides instructions by, for example, controlling one or more voltage, current, or pressure sources (not shown). Processor 830 may be a separate device as shown in fig. 8 or may be a processor or controller of separate device 810 or mass spectrometer 820. Processor 830 may be, but is not limited to, a controller, a computer, a microprocessor, the computer system of fig. 1, or any device capable of sending and receiving control signals and data and capable of processing data.

Processor 830 instructs separation device 810 to separate compounds from the sample over a period of time. Separation device 810 may be an HPLC system as shown in fig. 8. In various alternative embodiments, separation device 810 may be any type of separation device for a mass spectrometer, including, but not limited to, a Liquid Chromatography (LC) device, a gas chromatography device, a capillary electrophoresis device, or an ion transfer device.

Processor 830 instructs mass spectrometer 820 to measure a plurality of intensities of at least one ion of the separated compounds over a period of time, thereby generating a chromatogram. The mass spectrometer 820 may be a quadrupole mass spectrometer as shown in fig. 8. In various alternative embodiments, mass spectrometer 820 may be any type of mass spectrometer including, but not limited to, a quadrupole or triple quadrupole (QqQ), an ion trap, an orbitrap, a time-of-flight (TOF) mass spectrometer, or a Fourier Transform (FT) mass spectrometer.

Processor 830 uses a peak finding algorithm to identify at least one peak of at least one ion from the chromatogram. Processor 830 also uses a peak finding algorithm to calculate two or more different peak integration regions for at least one peak by applying the peak finding algorithm with two or more different values of at least one peak parameter without manually and iteratively adjusting the two or more different values.

In various embodiments, processor 830 simultaneously displays two or more plots of at least one peak on display device 831, each plot graphically showing a different peak integration region of two or more different peak integration regions. The display device 831 may be a display of the processor 830 as shown in fig. 8. In various alternative embodiments, display device 831 may be a display of another processor or computer (not shown), including, but not limited to, a processor or computer of separation device 810 or mass spectrometer 820.

In various embodiments, processor 830 receives data from user selection device 832 indicating a user selection of one of two or more drawings. The user selection device 832 may be a keyboard of the processor 830 as shown in fig. 8. In various alternative embodiments, user selection device 832 may be a touch screen of display device 831, a mouse, a keypad, or any other type of input device of processor 830 or another processor or computer (not shown), including, but not limited to, a display of a processor or computer of separation device 810 or mass spectrometer 820.

In various embodiments, two or more different values of at least one peak finding parameter for calculating two or more different peak integration regions are predetermined and received by processor 830. Two or more different values are determined by a system administrator and input to processor 830 by the administrator.

In various alternative embodiments, two or more different values are generated by processor 830. For example, two or more different values for at least one peak shaver parameter are generated to represent each different possible value within the selected range for the at least one peak shaver parameter.

Alternatively, two or more different values for the at least one peak shaver parameter are generated to represent a subset of each different possible value within the selected range for the at least one peak shaver parameter. In various embodiments, the subset is found by: how the peak integration area changes according to the value of the at least one peak finding parameter is calculated, a peak integration area change threshold is selected, and only the value of the at least one peak finding parameter that causes the peak integration area change to exceed the peak integration area change threshold is included in the subset. For example, fig. 7 shows the results from calculating how the peak integral area varies according to the value of the peak split factor parameter. Fig. 7 shows that only three peak split factor parameter values significantly change the peak integration region. As described above, there are only three values within the range of analysis (assuming a useful range).

In various embodiments, some other output from the peak finder may be used in addition to selecting the peak integral region variation threshold. For example, the beginning or end of a peak may be used.

In various embodiments, the peak finding algorithm used may be a combination of two or more peak finding algorithms.

In various embodiments, processor 830 further calculates a numerical area value for each of the two or more different peak integration regions. Processor 830 then displays the calculated numerical area value with each of the two or more plots.

In various embodiments, each of the two or more plots graphically illustrates a different peak integration region by shading the different peak integration region and by displaying a different peak baseline.

In various embodiments, processor 830 further determines a selected one of the two or more different peak integration regions from a selection of one of the two or more plots. Processor 830 calculates a numerical area value of the selected peak integration region. Finally, processor 830 calculates the amount of the compound in the sample based on the numerical area value.

In various embodiments, processor 830 further displays at least one peak-finding parameter and a value for the at least one peak-finding parameter on display device 831 along with each of the two or more plots. For example, the value for at least one peak finding parameter is editable.

In various alternative embodiments, the peak shaver parameters and peak shaver parameter values are not displayed with two or more plots.

Chromatographic peak integration method

Fig. 9 is a flow chart illustrating a method 900 for selecting an integration region of a chromatographic peak, in accordance with various embodiments.

In step 910 of method 900, a processor is used to instruct a separation device to separate compounds from a sample over a period of time.

In step 920, a processor is used to instruct a mass spectrometer to measure a plurality of intensities of at least one ion of the separated compounds over a period of time, thereby producing a chromatogram.

In step 930, at least one peak of the at least one ion is identified from the chromatogram using a peak finding algorithm using a processor and two or more different peak integration regions of the at least one peak are calculated by applying the peak finding algorithm with two or more different values of the at least one peak finding parameter without requiring manual and iterative adjustments to the two or more different values.

In various embodiments, the processor is used to simultaneously display two or more plots of at least one peak on the display device, each plot graphically displaying a different peak integration region of the two or more different peak integration regions.

In various embodiments, a processor is used to receive data from a user selection device, the data indicating a user selection of one of two or more drawings.

Chromatographic peak integral computer program product

In various embodiments, the computer program product comprises a tangible computer-readable storage medium whose contents include a program with instructions being executed on a processor in order to perform a method for selecting an integration region of a chromatographic peak. The method is performed by a system comprising one or more different software modules.

Fig. 10 is a schematic diagram of a system 1000 including one or more different software modules that perform a method for selecting integration regions of chromatographic peaks, in accordance with various embodiments. The system 1000 includes a control module 1010 and an analysis module 1020.

The control module 1010 instructs the separation device to separate compounds from the sample over a period of time. The control module 1010 instructs the mass spectrometer to measure a plurality of intensities of at least one ion of the separated compounds over a period of time, thereby generating a chromatogram.

The analysis module 1020 uses a peak finding algorithm to identify at least one peak of the at least one ion from the chromatogram. The analysis module 1020 calculates two or more different peak integration regions of the at least one peak by applying a peak finding algorithm with two or more different values of the at least one peak finding parameter without requiring manual and iterative adjustments to the two or more different values.

In various embodiments, the system 1000 further includes a display module 1030 and a user selection module 1040. The display module 1030 simultaneously displays two or more plots of at least one peak on the display device, each plot graphically showing a different peak integration region of the two or more different peak integration regions. The user selection module 1040 receives data from a user selection device that indicates a user selection of one of two or more drawings.

While the present teachings are described in connection with various embodiments, it is not intended to limit the present teachings to such embodiments. On the contrary, the present teachings encompass various alternatives, modifications, and equivalents, as will be appreciated by those of skill in the art.

Additionally, in describing various embodiments, the specification may have presented the method and/or process as a particular sequence of steps. The method or process should not be limited to the particular order of steps described, as long as the method or process does not rely on the particular order of steps set forth herein. As one of ordinary skill in the art will recognize, other sequences of steps may be possible. Accordingly, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. Furthermore, the claims directed to the method and/or process should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the various embodiments.

Claims

1. A system for selecting an integration region of a chromatographic peak, comprising:

a separation device;

a mass spectrometer; and

A processor, the processor

The separation device is instructed to separate compounds from the sample over a period of time,

Instructing the mass spectrometer to measure a plurality of intensities of at least one ion of the separated compounds over the period of time, thereby producing a chromatogram, and

Identifying at least one peak of the at least one ion from the chromatogram using a peak finding algorithm, and for each of the at least one peak:

Calculating two or more different kinds of peak integration regions of each peak by applying the peak finding algorithm with two or more different values of each of at least one peak finding parameter of the peak finding algorithm, each of the two or more different kinds of peak integration regions of each peak corresponding to a respective one of the two or more different values of each peak finding parameter, wherein the two or more different values of each peak finding parameter are predetermined without iterative adjustment of the value of each peak finding parameter, and

Selecting a value of a peak finding parameter corresponding to one of the two or more different kinds of peak integration regions of the each peak as a value of a peak finding parameter employed when the peak finding algorithm is applied to the each peak by receiving a selection of the one of the two or more different kinds of peak integration regions of the each peak, the selection of the one of the peak integration regions being based on a comparison between the two or more different kinds of peak integration regions of the each peak.

2. The system of claim 1, wherein the system further comprises a display device and a user selection device, and wherein the processor further

Simultaneously displaying on the display device two or more plots of the each of the at least one peak, each plot graphically showing a different one of the two or more different kinds of peak integration regions of the each peak, and

Data is received from the user selection device, the data indicating a user selection of one of the two or more drawings.

3. The system of claim 1, wherein the two or more different values of the each of the at least one peak shaver parameters are received by the processor.

4. The system of claim 1, wherein the two or more different values of the each of the at least one peak shaver parameters are generated by the processor.

5. The system of claim 4, wherein the two or more different values of the each of the at least one peak-finding parameters generated represent each different possible value within a selected range of the each of the at least one peak-finding parameters.

6. The system of claim 4, wherein the two or more different values of the each of the at least one peak-finding parameters generated represent a subset of each different possible value within the selected range of the each of the at least one peak-finding parameters.

7. The system of claim 6, wherein the subset is found by: calculating how the peak integration area varies according to the value of said each of said at least one peak finding parameter, selecting a peak integration area variation threshold and including in said subset only the value of said each of said at least one peak finding parameter that varies said peak integration area by more than said peak integration area variation threshold.

8. The system of claim 2, wherein the processor further calculates a numerical area value for each of the two or more different kinds of peak integration regions, and the processor displays the calculated numerical area value with each of the two or more plots.

9. The system of claim 2, wherein each of the two or more plots graphically displays a different peak integration region by shading the different peak integration region and by displaying a different peak baseline.

10. The system of claim 2, wherein the processor further determines a selected one of the two or more heterogeneous peak integration regions from a selection of one of the two or more plots, calculates a numerical area value of the selected peak integration region, and calculates an amount of the compound in the sample from the numerical area value.

11. The system of claim 2, wherein the processor is further to display the each of the at least one peak-seeking parameter and the value for the each of the at least one peak-seeking parameter on the display device with each of the two or more plots.

12. A method for selecting an integration region of a chromatographic peak, comprising:

instructing, using a processor, a separation device to separate compounds from a sample over a period of time;

Instructing, using the processor, a mass spectrometer to measure a plurality of intensities of at least one ion of the separated compounds over the period of time, thereby producing a chromatogram; and

Identifying, using the processor, at least one peak of the at least one ion from the chromatogram using a peak finding algorithm, and for each of the at least one peak:

13. The method of claim 12, further comprising

Simultaneously displaying, using the processor, two or more plots of the each of the at least one peak on a display device, each plot graphically showing a different peak integration region of the two or more different kinds of peak integration regions of the each peak, and

Data is received from a user selection device using the processor, the data indicating a user selection of one of the two or more drawings.

14. A non-transitory and tangible computer readable storage medium, the contents of which include a program with instructions that are executed on a processor to perform a method for selecting an integration region of a chromatographic peak, the method comprising:

Providing a system, wherein the system comprises one or more different software modules, and wherein the different software modules comprise a control module and an analysis module;

instructing the separation device to separate the compound from the sample over a period of time using the control module;

Instructing a mass spectrometer to measure a plurality of intensities of at least one ion of the separated compounds over the period of time using the control module, thereby producing a chromatogram; and

Identifying at least one peak of the at least one ion from the chromatogram using a peak finding algorithm using the analysis module, and for each of the at least one peak:

15. The computer-readable storage medium of claim 14, wherein the different software modules further comprise a display module and a user selection module, and wherein the method further comprises

Simultaneously displaying, using the display module, two or more plots of the each of the at least one peak on a display device, each plot graphically showing a different peak integration region of the two or more different kinds of peak integration regions of the each peak, and

Data is received from a user selection device using the user selection module, the data indicating a user selection of one of the two or more drawings.